Synthesis of sustainable activated carbon for nanocarbon composite and enhanced-performance supercapacitor application

This study aims to investigate the synthesis of nanocarbon composites from natural activated carbon (ACN) and nanocarbons derived from acetylene black (AB), carbon nanotubes (CNTs), and graphene (GP). The process of synthesizing nanocarbon composites from natural activated carbon was carried out in two stages: mixing activated carbon with nanocarbons in a ball mill for 4 h, followed by ultrasonication at 65 °C for 1 h, and drying the composite product. The results of physical characterization showed that the composition of the natural activated carbon and nanocarbon decreased the degree of graphitization, surface area, and crystallinity of the nanocarbon composites. Electrochemical characterization revealed that the nanocarbon composite composition enhanced capacitance, improved rate capability, reduced cell resistance (including ohmic, charge-transfer, and diffusion), and increased supercapacitor cell-cycle stability. The highest capacitance of 229.2 F g −1 was achieved in a supercapacitor cell using the ACN/AB/CNT/GP composite. The rate capability of ACN/AB/CNT/GP composite-based supercapacitor cells is 89%. Results from the cycle stability analysis show the capacitance retention of 103% after 10,000 cycles. The carbon nanocomposite increased the energy density and power of the supercapacitor cells from 5.1 Wh kg −1 and 303.6 W kg −1 to 8 Wh kg −1 and 447.5 W kg −1 , respectively. • Nanocarbon composites were synthesized via ball milling and ultrasonication. • Structural modification reduced graphitization, crystallinity, and surface area. • The ACN/AB/CNT/GP composite achieved a high specific capacitance of 229.2 F g⁻¹ . • Rate capability was 89% and cycle stability were reached over 10,000 cycles. • Energy and power densities increased, reaching 8 Wh kg⁻¹ and 447.5 W kg⁻¹ .